The OscSync
The OscSync has at its core a sawtooth oscillator
with a downgoing slope. On the flank of the sawtooth it syncs a second built in
osc that has a waveform that can be morphed between a triangle and a sawtooth.
A hardsync sound basically has two sonic
components, one is a formant effect that when swept gives a flanger-like sound,
the other is a pulse that is produced by the transient flank introduced on the
syncing moment. This transient has a level that depends on the frequency of the
synced osc and when swept it goes up and down in level in basically an unwanted
way. As this new transient has a lot of sonic energy in the high end of the
spectrum it doesn’t sound good on e.g. sine and triangle waves that by nature
do not have one or more transient flanks in their waveform. And so it is of
interest to suppress only this sync transient effect. For this a sync transient
suppressor is built into the osc and this makes the sync sweep sound as smooth
as silk, no matter the type of waveform.
Both the original sawtooth and the ‘transient
suppressed’ synced waveform are brought out on separate output connectors.
There is a subsquare divider built in that goes
into a built in VCA. This signal can be used to modulate the sync sweep. The
effect is that on every alternate wavecycle the formant structure caused by the
sync is alternated by two settings that depend on the level of modulation. This
gives a ‘talkative’ effect on the sound. This subsquare is also brought out on
a connector to modulate e.g. a filter that has the basic sawtooth wave as its
input.
The sub out can also be used in a mix with either
the sawtooth or the synced sound to add a suboctave bottom to the sound.
There also is a built in S&H that triggers on
the flank of the main sawtooth osc. It has its own input and output, but by
default the input is normalized to the internal transient suppressor and
samples the level of the sync transient. The output is normalized to the
modulation inputs of the main pitch, the subsquare modulation level and the
sync sweep CV inputs. The sync transient depends on the pitch of the synced
oscillator in an ‘irregular way’ it can be fed back to the sync sweep input to
cause a ‘chaotic’ modulation on the sync sweep. This effect is not unlike the
effect of a rungler circuit. When also fed back to the main pitch modulation
input it will change the length of the wave cycle with an amount that will be
different for each cycle. As the oscillator can go into the LFO range this can
also create quite nice effects.
The normalizations can of course be overridden by
plugging in a cable at the CV input connectors or close the modulation level
knobs.
The S&H can also be used with an external
audio signal to ‘bit crunch’ that signal.
The sync transient suppression is what makes this
osc unique. The S&H and subsquare make it great for a vast range of
different sonic effects.
As this oscillator can do a
range from quite traditional synth and sync sounds, but with a very smooth
sound, up to rungler-like chaotic sounds the Twinpeak is the prime suspect to
do filtering on the several output signals from the osc. The two Twinpeak
‘peaks’ can e.g. be modulated separately by the subsquare output, the S&H
output or an audio range signal from e.g. the OscHRM or an LFO and/or envelope.
Here is the flowchart of the OscSync :
Chris David aka Osc1899 filmed these videos of Rob explaining the module :
Also this video of the Novars workshop is quite nice :
I also recorded a small series of demos when I received the OscSync Rob Hordijk OscSync demos
And there are also more videos and audio available. Check Todd Barton's channels and be amazed ;-)
Thanks again to Todd for providing the picture of the module.
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